JP2020007174A - Production method of glass article - Google Patents

Abstract

To produce a high quality glass article at a restart of operation by preventing improper foreign materials from contaminating molten glass to be supplied to molding means at a period between exchange of a transfer device and the restart of operation.SOLUTION: A production method of a glass article includes a melting step for forming molten glass Gm, a transfer step for transferring the molten glass Gm to molding means 4 by a transfer device 3 including a plurality of transfer vessels 5-9, a molding step for molding the molten glass Gm to a predetermined shape by the molding means 4, and an exchanging step for exchanging the transfer device 3 while holding the molten glass Gm in a melting furnace 2. At a period between attaching the transfer device 3 to the melting furnace 2 in the exchanging step and restarting the molding step, the molten glass Gm is discharged from the transfer device 3 to the outside for preparation while sending the molten glass Gm from the melting furnace 2 to the transfer device 3.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a method for manufacturing a glass article, and more particularly, to a method for manufacturing a glass article having an exchange step of exchanging a transfer device for transferring molten glass flowing out of a melting furnace to a forming means.

  As is well known, when manufacturing a glass article, molten glass flowing out of a melting furnace is supplied to a forming apparatus by a transfer device. The transfer device has a transfer container for transferring the molten glass. The melting furnace plays a role of heating and melting the glass raw material and sending the molten glass to a transfer device.

  As an example, Patent Document 1 discloses a transfer device including a melting furnace and a plurality of transfer containers. As the transfer container, a fining pipe, a stirring pot, a cooling pipe, a pot, and the like are listed in order from the upstream side. In the transfer channel including these transfer containers, at least a portion that comes into contact with the molten glass during operation is generally formed of a member made of thin platinum or a platinum alloy.

JP 2014-19629 A

  By the way, when the transfer device has deteriorated over time or has failed, repair work of the transfer device is performed, and the transfer device is replaced with a repaired transfer device or replaced with a new transfer device. In this case, the transfer device is temporarily removed from the melting furnace, and after a predetermined period of time, a repaired or new transfer device is attached to the melting furnace.

  When the transfer apparatus is replaced, if the melting furnace from which the transfer apparatus has been removed is left unheated and left as it is, the molten glass in the melting furnace solidifies (including semi-solidification). Therefore, at the time of re-operation, there is a problem that the temperature-raising process for converting the solidified glass into molten glass is prolonged, and the labor and labor for raising the temperature are increased.

  To solve this problem, it is necessary to keep the melting furnace heated and hold the molten glass in the melting furnace after the transfer device is removed and before its replacement is completed. Conceivable. However, if the melting furnace is kept heated, the molten glass in the melting furnace is cooked. The melting furnace includes, for example, a refractory such as zirconia, and a plate made of a thin noble metal (for example, platinum or a platinum alloy) is attached to an appropriate position on an inner wall surface.

  Therefore, in the melting furnace, platinum, zirconia, and the like melt into the cooked molten glass. When the molten glass flows through the transfer device at the time of re-operation, needle-like foreign matters (hereinafter, referred to as needle-like bumps) made of a noble metal or the like are generated due to the stirring action in the stirring pot. Further, when the molten glass is supplied to a molded body of a molding unit that executes, for example, an overflow down draw method, needle-like butter sticks to a wall surface of the molded body.

  In such a state, when the molten glass supplied from the melting furnace to the molding means through the transfer device flows down on both side walls of the molded body, the needle-shaped butters adhered to the both side walls have respective molten glass. To the contact surface. Then, the sheet glass obtained by fusing these molten glasses at the lower end of the molded body has a state in which needle-like butterflies enter a portion corresponding to a joining surface at the time of fusing. The needle-like bumps are defects and may cause fatal problems such as defective products. In addition, since the needle-shaped butter is stuck to the wall surface of the molded body, it is not possible to eliminate a product defect or the like due to the needle-shaped butter after a long period of time (for example, about one month or two months).

  From the above viewpoint, the present invention is to prevent unreasonable foreign matter from being mixed into the molten glass to be supplied to the forming means during the period from the exchange of the transfer device to the restart, and from the start of the restart. It is an object to be able to manufacture a high-quality glass article.

  The present invention was devised to solve the above problems, a melting step of heating and melting glass raw material in a melting furnace to generate a molten glass, and a transfer step of transferring the molten glass generated in the melting furnace by a transfer device, Forming a molten glass supplied from the transfer device into a predetermined shape by forming means, wherein the transferring step and the forming step are interrupted, and the melting furnace is stopped. In a state where the molten glass is held, the method has an exchange step of exchanging the transfer device, and in the exchange step, attaching the transfer device to the melting furnace and before starting the forming process. The method is characterized in that a preparation process for discharging molten glass in the transfer device to the outside while flowing the molten glass from the furnace into the transfer device is performed.

  According to such a method, the heating by the melting furnace is not stopped until the transfer device is attached to the melting furnace in the transfer device replacement process, so that the glass is not solidified in the melting furnace, and the glass is melted. You will be holding glass. When the transfer device is attached to the melting furnace, the molten glass flows from the melting furnace into the transfer device by performing the preparation process. The molten glass flows through the transfer device and is discharged outside from the transfer device before being supplied to the forming means. This operation is performed, for example, until the entire amount of the molten glass including platinum and the like generated in the melting furnace is completely discharged to the outside through the transfer device. Therefore, at the start of the forming step, the concentration of undesired foreign substances such as needle-like butter in the molten glass supplied from the melting furnace to the forming means through the transfer device can be reduced. Thereby, it is possible to reduce the intrusion of illegal foreign matters into the glass article manufactured through the forming means from the start of the restart. As a result, it is possible to prevent the occurrence of a product defect or the like.

  In the above method, the molten glass may be discharged to the outside through a drain hole opened in the inner bottom surface of the stirring pot provided in the transfer device when the preparation process is performed.

  With this configuration, since the temperature of the molten glass in the stirring pot is lower than the temperature of the molten glass in the melting furnace or the fining tank, the molten glass can be discharged outside at a suitable flow rate, and the discharged molten glass can be discharged. Handling of glass becomes easy.

  In this case, it is preferable that the transfer device includes a plurality of the stirring pots, and discharges the molten glass to the outside through drain holes respectively opened on the inner bottom surfaces of all the stirring pots when the preparation process is performed.

  In this way, the time required for discharging the entire amount of molten glass including platinum and the like generated in the melting furnace from the transfer device is shortened. By this. The molten glass can be efficiently discharged while appropriately adjusting the flow rate of the molten glass discharged from the transfer device.

  In the above-described method, the transfer device includes a fining tank disposed upstream of the stirring pot, and a gate disposed between the fining tank and the stirring pot. It is preferable that the flow rate of the molten glass is adjusted by changing an opening degree of the flow path of the transfer device by a gate.

  Here, the flow rate of the molten glass discharged from the transfer device to the outside can be adjusted by changing the temperature of the molten glass in the melting furnace, the refining tank, and the stirring pot, respectively. If the difference between the temperature and the temperature during operation is large, it takes time to adjust the temperature of the molten glass after the completion of the preparation process. Therefore, there is a limit to the flow rate adjustment based on the temperature of the molten glass. In this method, the flow rate of the molten glass is adjusted by changing the degree of opening of the flow path at the gate, so that the temperature of the molten glass in the melting furnace or the refining tank is maintained at a desired temperature, and the method is simplified. It is possible to adjust the flow rate.

  In the above method, between the start of the exchange step and the start of the preparation process, the upper layer portion of the molten glass of the melting furnace, so as to be discharged to the outside by an overflow device provided in the melting furnace. Is also good.

  Here, from the start of the replacement process to the start of the preparation process, since the transfer device is removed from the melting furnace, the molten glass in the melting furnace may be in a state of being cooked. However, in this method, since the upper layer portion of the molten glass in the melting furnace is discharged outside by the overflow device, the molten glass flows. This makes it difficult for the molten glass to be cooked in the melting furnace, thereby suppressing an increase in the concentration of platinum or the like. When discharging the upper part of the molten glass from the melting furnace to the outside, the glass material should be appropriately replenished to the melting furnace and the liquid level of the molten glass in the melting furnace should be kept constant. Is preferred.

  In the above method, at the time of performing the preparatory process, the molten glass of the melting furnace is discharged from the transfer device to the outside while flowing into the transfer device from below an overflow portion by the overflow device. Is preferred.

  Here, as described above, even if the upper layer portion of the molten glass overflows from the melting furnace by the overflow device, foreign substances such as platinum and zirconia remain in the middle layer portion and the lower layer portion of the molten glass. obtain. However, in this method, at the time of performing the preparatory processing, the molten glass is discharged from the lower side of the overflow portion of the melting furnace to the outside while flowing into the transfer device. Thus, the middle layer and the lower layer of the molten glass, in which foreign matter such as platinum can remain, can be discharged to the outside after flowing into the transfer device.

  In the above method, when the melting furnace is a single melter having one melting space, the total amount W1 (kg) of the molten glass discharged from the inside of the transfer device in the preparation process to the outside is determined by the melting in the exchange step. The ratio (W1 / W2) to the total amount of molten glass W2 (kg) held in the furnace is preferably 1 or more. Further, when the melting furnace is a multi-melter in which a plurality of melting spaces are connected, the total amount W1 (kg) of the molten glass discharged to the outside from the inside of the transfer device in the preparation processing is equal to the total amount of the melting glass in the replacing process. It is preferable that the ratio (W1 / W3) to the total amount W3 (kg) of the molten glass held in the melting space located at the most downstream in the inside is 1 or more.

  In this way, most of the molten glass stored in the melting furnace is discharged from the transfer device to the outside. Thus, the molten glass stored in the melting furnace and having an increased concentration of platinum or the like can be prevented from being supplied to the forming means.

  According to the present invention, it is possible to reduce the concentration of undesired foreign matter in the molten glass to be supplied to the forming means during the period from the replacement of the transfer device to the restart of the transfer device, and the high concentration from the start of the restart. It becomes possible to manufacture high-quality glass articles.

It is a schematic side view showing the whole composition of the manufacturing device for carrying out the manufacturing method of the glass article concerning the embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a longitudinal side view which shows the transfer apparatus which is the principal part of the manufacturing apparatus for implementing the manufacturing method of the glass article which concerns on embodiment of this invention. It is a vertical side view which shows the structure of the principal part in the replacement | exchange process in the manufacturing apparatus for implementing the manufacturing method of the glass article which concerns on embodiment of this invention. It is a vertical side view which shows the structure of the principal part in the replacement | exchange process in the manufacturing apparatus for implementing the manufacturing method of the glass article which concerns on embodiment of this invention. FIG. 5 is a vertical sectional front view taken along line AA of FIG. 4. It is a vertical side view which shows the state of the principal part which is performing the preparation process in the manufacturing method of the glass article which concerns on embodiment of this invention.

  Hereinafter, a method for manufacturing a glass article according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 illustrates a production apparatus for carrying out the method for producing a glass article according to the present invention. As shown in FIG. 1, the manufacturing apparatus 1 is roughly divided into a melting furnace 2 arranged at an upstream end for heating and melting a glass raw material, and a molten glass Gm flowing out of the melting furnace 2 to a molding means 4. The apparatus includes a transfer device 3 and forming means 4 for forming the molten glass Gm supplied from the transfer device 3 into a band-shaped plate glass Gp.

  The melting furnace 2 generates the molten glass Gm by heating and melting the glass raw material, and continuously sends a predetermined amount of the molten glass Gm to the transfer device 3 while storing a large volume of the molten glass Gm.

  The transfer device 3 includes, in order from the upstream side, a refining tank 5, an attached tank 6 attached to the refining tank 5, a plurality of (two in the illustrated example) stirring pots 7, 8, and a cooling pipe 9 as transfer containers. , A pot 10. Each of these transfer containers 5 to 10 has an inlet into which the molten glass Gm flows, and an outlet through which the molten glass Gm flows out.

  More specifically, the fining tank 5 is for removing bubbles in the molten glass, and an attached tank 6 is connected downstream of the fining tank 5. A first stirring pot 7 on the upstream side and a second stirring pot 8 on the downstream side for homogenizing the molten glass Gm are disposed downstream of the attachment tank 6. When the manufacturing apparatus 1 is in operation, the stirring pots 7 and 8 accommodate stirring blades (stirrers) 7x and 8x that rotate around the axis. On the downstream side of the second stirring pot 8, a cooling pipe 9 is disposed adjacently, and on the downstream side of the cooling pipe 9, a pot 10 serving as a volume part for mainly adjusting the viscosity of the molten glass Gm is disposed adjacently. Have been. The downstream side of the cooling pipe 9 is inclined upward.

  The forming means 4 has a formed body 11 for forming the molten glass Gm by the overflow down draw method, and a large-diameter introduction pipe 12 for guiding the molten glass Gm to the formed body 11. The molten glass Gm is supplied to the introduction pipe 12 from the pot 10 of the transfer device 3.

  FIG. 2 is an enlarged vertical sectional view schematically showing the melting furnace 2 and the transfer device 3 during operation.

  As shown in the figure, the melting furnace 2 supplies molten glass Gm at about 1700 ° C. by charging a glass material into an internal space surrounded by a bottom wall 2c, a side wall 2d, and an upper wall 2e. Generate. The bottom wall 2c and the side wall 2d include a zirconia-based refractory. A thin plate made of a noble metal (for example, platinum or a platinum alloy) is adhered to the outlet 2b and its periphery in the side wall 2d of the melting furnace 2 (not shown). From the melting furnace 2, a fixed amount of molten glass Gm is continuously fed to the transfer device 3 per unit time. By continuously replenishing and feeding glass materials into the melting furnace 2, the liquid level of the molten glass Gm in the melting furnace 2 is maintained substantially constant.

  The outlet 2b of the melting furnace 2 is formed below the side wall (downstream side wall) 2d. The outlet 2 b communicates with the inlet 5 a of the fining tank 5 via the upstream connection pipe 13. The outlet 5b of the fining tank 5 overlaps and communicates with the inlet 6a of the attached tank 6. The outlet 6b of the attachment tank 6 communicates with the inlet 7a of the first stirring pot 7 via the intermediate connection pipe 14. The inflow port 7a of the first stirring pot 7 is provided at an upper portion of the peripheral wall. The outlet 7b of the first stirring pot 7 communicates with the inlet 8a of the second stirring pot 8 via the downstream connection pipe 15. The outlet 7b of the first stirring pot 7 is provided at a lower portion of the peripheral wall, and the inlet 8a of the second stirring pot 8 is provided at an upper portion of the peripheral wall. These stirring pots 7, 8 are arranged at the same height. The downstream side connection pipe 15 has a downstream side inclined upward. The outlet 8b of the second stirring pot 8 overlaps and communicates with the inlet 9a of the cooling pipe 9. The outlet 8b of the second stirring pot 8 is provided at a lower portion of the peripheral wall. The downstream side of the cooling pipe 9 is inclined upward. The outlet 9b of the cooling pipe 9 overlaps and communicates with the inlet 10a of the pot 10. The pot 10 has an upper large diameter portion 10x and a lower small diameter portion 10y. The inlet 10a of the pot 10 is provided on the peripheral wall of the large diameter portion 10x, and the outlet 10b is provided at the lower end of the small diameter portion 10y. The small diameter portion 10y of the pot 10 is inserted into the introduction pipe 12 of the molding means 4. The lower end of the small diameter portion 10y is immersed in the molten glass Gm in the introduction pipe 12.

  In the transfer channel configured by the transfer containers 5 to 10 and the connection pipes 13 to 15, at least a portion (in this embodiment, the entire inner surface of the transfer channel) in contact with the molten glass Gm is thin platinum or platinum. It is formed of a member made of a platinum alloy. The periphery of these members is covered with a refractory (not shown). The transfer passage is electrically heated and can be adjusted in temperature for each of the transfer containers 5 to 10 and each of the connection pipes 13 to 15.

  The manufacturing apparatus 1 having the above configuration executes the following steps. That is, the method for producing a glass article according to the present invention includes a melting step of generating molten glass Gm in the melting furnace 2 and a transfer step of transferring the molten glass Gm flowing out of the melting furnace 2 to the forming means 4 by the transfer device 3. And a forming step of forming the molten glass Gm supplied from the transfer device 3 into a predetermined shape by the forming means 4. Further, this manufacturing method includes an exchange step of exchanging the transfer device 3 while interrupting the transfer step and the forming step and holding the molten glass Gm in the melting furnace 2. Then, a preparation process is performed after the transfer device 3 is attached to the melting furnace 2 in the replacement process and before the molding process is started.

  FIG. 3 illustrates a state in which the transfer device 3 is detached (disconnected) from the melting furnace 2 in the replacement process. This replacement step is for performing a repair work on the transfer device 3. In this embodiment, the molding device 4 is detached from the transfer device 3, but the molding device 4 may be attached to the transfer device 3. In the replacement step, only the transfer device 3 may be replaced, or the molding means 4 may be replaced together with the transfer device 3.

  As shown in the figure, the outflow port 2 b of the melting furnace 2 is closed by a blocking plate 16. Since the melting furnace 2 is continuously heated as in the operation, the temperature of the molten glass Gm in the melting furnace 2 is maintained at a high temperature of, for example, about 1700 ° C. Therefore, platinum, zirconia, and the like are in a state in which the middle portion Gm1 and the lower portion Gm2 of the molten glass Gm in the melting furnace 2 are melted.

  A duct 2f is mounted on a side wall (upstream side wall) 2d of the melting furnace 2, and the melting furnace 2 includes an overflow device constituted by the duct 2f. The upper layer portion Gm3 (cross-hatched portion) of the molten glass Gm in the melting furnace 2 is discharged outside through the duct 2f. Since the glass material is appropriately replenished into the melting furnace 2, the liquid level of the molten glass Gm in the melting furnace 2 is kept constant (for example, the liquid level during operation). By performing such a process, the molten glass Gm in the melting furnace 2 flows. This makes it difficult for the molten glass Gm to be cooked in the melting furnace 2 and suppresses an increase in the concentration of platinum, zirconia, or the like.

  In the transfer device 3, all of the transfer containers 5 to 10 and the connection pipes 13 to 15 are all empty. Among these, the stirring blades 7x, 8x are extracted from the first and second stirring pots 7, 8. A gate 17 for opening and closing the flow path and changing the degree of opening of the flow path is inserted into the attachment tank 6. More specifically, as shown in FIGS. 4 and 5, a gap 18 is provided between the lower surface 6 m of the attachment tank 6 and the bottom 16 m of the gate 17. The gap 18 is a flow path (a narrowed flow path) through which the molten glass Gm flows. The gate 17 is moved up and down by a lifting mechanism (not shown) to open and close the flow path and change the degree of opening of the flow path, thereby adjusting the flow rate of the molten glass Gm flowing toward the downstream side. A thin plate member 19 made of platinum or a platinum alloy is adhered to the front surface portion 17a and the back surface portion 17b, the side surface portions 17c, and the bottom surface portion 17m of the refractory forming the gate 17. The gate 17 has a U-shape from both side surfaces 17c to the bottom surface 17m.

  The fining tank 5 has a pipe shape. The attachment tank 6 has a pipe shape, but only a portion into which the gate 17 is inserted has a U shape as shown in FIG. The passage area of the fining tank 5 is larger than the passage area of the attachment tank 6, and the passage area of the attachment tank 6 is larger than the passage area of the intermediate connection pipe 14. Specifically, the lowest part of the lower surface part 5m of the refining tank 5, the lower part of the lower surface part 6m of the attachment tank 6, and the lowest part of the lower surface part 14m of the intermediate connecting pipe 14 are at the same height position. The uppermost portion of the upper surface portion 5n of the refining tank 5 is higher than the uppermost portion of the upper surface portion 6n of the additional tank 6, and the uppermost portion of the upper surface portion 6n of the additional tank 6 is higher than the uppermost portion 14n of the intermediate connection pipe 14. Higher than the top.

  FIG. 6 illustrates a state in which the transfer device 3 after the renovation work is attached to the melting furnace 2 and a preparation process is being performed. In this embodiment, the preparatory process is executed from the middle of the replacement process to the time when the molding device 4 is attached to the transfer device 3 and the molding process starts. If the molding device 4 is attached to the transfer device 3 at this time, the preparation process is executed from the end of the replacement process to the start of the molding process. In this embodiment, while the preparation process is being performed, the upper layer portion Gm of the molten glass Gm is not discharged to the outside by the overflow device described above, but may be performed.

  As shown in the figure, the molten glass Gm flowing out of the lower outlet 2b of the melting furnace 2 continues to flow into the transfer device 3. The molten glass Gm (particularly, the middle layer portion Gm1 and the lower layer portion Gm2) has a high concentration of platinum or the like which causes the occurrence of needle-like bumps. Then, as shown in the figure, the molten glass Gm is settled in a retained state while flowing at a portion from the upstream connection pipe 13 of the transfer device 3 to the second stirring pot 8. In the preparation process of the present embodiment, the liquid level of the molten glass Gm in the second stirring pot 8 is lower than the inlet 9a of the cooling pipe 9, and the molten glass Gm does not flow into the cooling pipe 9. The liquid level of the molten glass Gm in the second stirring pot 8 may be higher than the inlet 9 a of the cooling pipe 9 so that the molten glass Gm flows into the cooling pipe 9. In the latter case, the liquid level of the molten glass Gm in the second stirring pot 8 is set lower than the outlet 9 b of the cooling pipe 9.

  In the preparation process, the flow rate of the molten glass Gm flowing into the first and second stirring pots 7 and 8 is adjusted by the gate 17. The drain holes 7g and 8g of the first and second stirring pots 7 and 8 are all open to the atmosphere. Therefore, the molten glass Gm in the first and second stirring pots 7 and 8 is continuously discharged downward through the drain holes 7g and 8g.

  The flow passage area of the drain hole 7g of the first stirring pot 7 is smaller than the flow passage area of each of the inlet 7a and the outlet 7b of the first stirring pot 7. Also, the flow passage area of the drain hole 8g of the second stirring pot 8 is smaller than the flow passage area of each of the inlet 8a and the outlet 8b of the second stirring pot 8. Thereby, the flow rate of the molten glass Gm discharged from the drain holes 7g and 8g of the first and second stirring pots 7 and 8 becomes more suitable. Furthermore, since the molten glass Gm is simultaneously discharged from the drain holes 7g and 8g of the two stirring pots 7 and 8, the time required for the discharge is reduced.

  This preparation process is performed until the concentration of platinum or the like contained in the molten glass Gm in the melting furnace 2 and the transfer device 3 is reduced to a level that does not cause a problem in the manufactured glass article. In the present embodiment, the total amount W1 (kg) of the molten glass Gm discharged from the inside of the transfer device 3 to the outside in the preparation process is equal to the total amount W2 (kg) of the molten glass Gm held in the melting furnace 2 in the replacement process. As a result, most of the molten glass Gm accumulated in the melting furnace 2 and having an increased concentration of platinum or the like, which is a cause of generation of needle-like bumps, is discharged to the outside through the transfer device 3. As a result, in the melting furnace 2 and the transfer device 3, the molten glass Gm in which the concentration of platinum or the like, which is a cause of needle-like bumps, has increased is scarcely left. From the viewpoint of reducing the concentration of platinum and the like contained in the molten glass Gm in the melting furnace 2 and the transfer device 3, W1 / W2 can be set to, for example, 0.5 or more, and preferably 1 or more. On the other hand, from the viewpoint of preventing an increase in manufacturing cost due to discharge of the molten glass Gm, W1 / W2 is preferably set to 1.5 or less.

  Although the melting furnace 2 of the present embodiment is a single melter having one melting space, the melting furnace 2 may be a multi-melter in which a plurality of melting spaces are connected. In the case of a multi-melter, from the viewpoint of reducing the concentration of platinum or the like contained in the molten glass Gm in the melting furnace 2 and the transfer device 3, the total amount of the molten glass Gm held in the most downstream melting space in the exchange process is W3 (Kg), W1 / W3 is preferably 1 or more. On the other hand, from the viewpoint of preventing an increase in production cost due to discharge of the molten glass Gm, W1 / W3 is preferably set to 1.5 or less.

  Thereafter, when the transfer step and the forming step are started, as shown in FIGS. 1 and 2, the forming means 4 is attached to the transfer device 3, and the drain holes 7 g of the first and second stirring pots 7 and 8 are formed. , 8 g are closed. At this time, the gate 17 is removed from the attachment tank 6, and an opening for inserting and removing the gate 17 is covered with a lid member 20 made of platinum or a platinum alloy.

  Further, when the transfer step and the forming step are started, the molten glass Gm existing in the melting furnace 2 and the transfer apparatus 3 has a reduced concentration of platinum or the like which causes generation of needle-like bumps. Thereby, it is possible to reduce needles and the like from entering the glass plate manufactured by the manufacturing apparatus 1 from the start of the forming process, and it is possible to prevent the occurrence of product defects and the like.

  The present invention is not limited to the above embodiment, and various variations are possible as exemplified below.

  In the above-described embodiment, the molten glass Gm is discharged from the drain holes 7g and 8g of the first and second stirring pots 7 and 8 when performing the preparation process. The glass Gm may be discharged.

  In the above embodiment, the case where two stirring pots 7 and 8 are provided is illustrated, but the present invention can be similarly applied to a case where three or more stirring pots are provided. In this case, it is preferable to discharge the molten glass Gm from all the drain holes of the three or more stirring pots when performing the preparation process.

  In the above embodiment, the gate 17 is provided in the attachment tank 6, but the flow rate may be adjusted only by adjusting the temperature of the molten glass Gm without using the gate 17. The location of the gate 17 may be another location as long as it is a flow path between the fining tank 5 and the first stirring pot 7.

  In the above embodiment, the gate 17 is used as a member for adjusting the flow rate of the molten glass Gm flowing through the transfer device. However, for example, between the fining tank 5 and the first stirring pot 7, an inlet is provided on the peripheral wall and the bottom is provided. A structure having a container having an outlet on the wall and having a plunger for adjusting the amount of molten glass flowing out from the outlet (this structure itself is well known) is adopted, and the plunger is used as a member for adjusting the flow rate. May be used.

  In the above embodiment, the forming means 4 forms the band-shaped plate glass Gp. However, the forming means 4 may be formed into another shape corresponding to the glass article.

1 Manufacturing Equipment 2 Melting Furnace 2b Outlet 2f Duct (Overflow Device)
Reference Signs List 3 Transfer device 4 Forming means 5 Refining tank 6 Attached tank 7 Stirring pot 7g Drain hole 8 Stirring pot 8g Drain hole 9 Cooling pipe 11 Molded body

Claims (8)

A melting step of heating and melting a glass raw material in a melting furnace to generate a molten glass, a transferring step of transferring the molten glass generated in the melting furnace to a forming means by a transferring device, and a molten glass supplied from the transferring device. A molding step of molding into a predetermined shape by the molding means, comprising:
The transfer step and the forming step are interrupted, and in a state in which the molten glass is held in the melting furnace, a replacement step of replacing the transfer device,
Between the time when the transfer device is attached to the melting furnace in the exchanging process and the time when the forming process is started, the molten glass in the transfer device is discharged to the outside while the molten glass flows from the melting furnace into the transfer device. A method for manufacturing a glass article, comprising performing a preparation process for discharging.   2. The method according to claim 1, wherein at the time of performing the preparation processing, the molten glass is discharged to the outside from a drain hole opened in an inner bottom surface of the stirring pot provided in the transfer device. 3.   3. The transfer device according to claim 2, wherein the transfer device includes a plurality of the stirring pots, and discharges the molten glass to the outside through drain holes respectively opened on the inner bottom surfaces of all the stirring pots when the preparation process is performed. 4. A method for manufacturing a glass article. The transfer device includes a fining tank disposed upstream of the stirring pot, and a gate disposed between the fining tank and the stirring pot,
The method according to claim 3, wherein when the preparing step is performed, the flow rate of the molten glass is adjusted by changing an opening of a flow path of the transfer device by the gate.   2. An upper layer portion of the molten glass of the melting furnace is discharged outside by an overflow device provided in the melting furnace during a period from the start of the replacement step to the start of the preparation processing. 5. The method for producing a glass article according to any one of items 1 to 4.   The method of manufacturing a glass article according to claim 5, wherein, at the time of performing the preparation processing, the molten glass in the melting furnace is caused to flow into the transfer device from below an overflow portion of the overflow device. The melting furnace is a single melter having one melting space,
The total amount W1 (kg) of the molten glass discharged from the inside of the transfer device to the outside in the preparation process is a ratio (W1 / W2) to the total amount W2 (kg) of the molten glass held in the melting furnace in the exchange step. The method for producing a glass article according to claim 1, wherein the number is one or more. The melting furnace is a multi-melter in which a plurality of melting spaces are connected,
The total amount W1 (kg) of the molten glass discharged from the inside of the transfer device to the outside in the preparation process is the total amount of the molten glass held in the lowermost one of the plurality of melting spaces in the exchange process. The method according to any one of claims 1 to 6, wherein a ratio (W1 / W3) to W3 (kg) is 1 or more.

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